Coating zinc and cadmium



Patented Dec. 9, 1930 PATENT OFFICE ALAIDAB PACZ, OF EAST CLEVELAND,OHIO COATING ZINC AND CADMIUM No Drawing.

This invention relates to the coating of metals either for preservativeor decorative purposes and has for its object the provision of a simple,convenient, and inexpensive process whereby zinc and cadmium can beprovided with a thin adherent coatin which is permanent andnon-corrodible un er all ordinary conditions, which is artistic andattractive to the eye when left naked, and

it which constitutes a satisfactory and enduring foundation for paint,enamel and other coatings; the provision of a process which shall berapid and economical and which does not require the employment of wires,electric contacts, and electric potential; the provision of a simpleprocess whereb coatings of different colors can be control ablyproduced; while further objects and advanta es of the invention willbecome apparent as t e description proceeds.

It is well known that zinc and cadmium are difficult metals to coat orcolor economicall since the usual quickly applied coatings, bot

metallic and non-metallic, fail to adhere successfully thereto; andwhile articles of pure zinc and cadmium are quite rare, articles havinga protective coating of those metals are very common, as well as certainalloys which contain the same and as a result exhibit certain chemicaland electrical peculiarities commonly associated with these sub stances.

My invention is based u on the peculiar properties of certain mo ybdenumcompounds, and consists essentiall in depositin upon the surface of theartic e to be coate or colored an adherin coating of substantial densityand bar ness consisting apparently of one or more of the lower oxides ofmolybdenum formed thereon in situ.

However, a pure solution of the mol bdenum compound is not sufficientbut the a dition of certain other substances is necessary to produce theresults in view.

In the performance of my said invention I subject the articles to theaction of a solution containing a soluble molybdate, and othersubstances which accelerate and intensity the action thereof. This ispreferably effected by immersing the articles bodily Application filedHay -28, 1827. Serial No. 195,140.

in a solution of the requisite composition until the desired coating isobtained, although I do not exclude spraying, painting, etc. Themolybdate used is preferably that of ammonium and the strength of thesolution is preferably from about to, say, 2% of ammonium m'olybdate.This material alone, at least in the cold and without electricalpotential, is too slow in action at least for ielding dark coatings.

T e presence of different acid radicals aocelerates and intensifies theaction. Of the many scores of substances I have tested the best resultsI have so far achieved have been with sulphuric acid in the form ofammonium sulphate, although I do not limit myself thereto since theremay be other substances which will produce equivalent results. I preferto employ an amount of this activating material in excess of themolybate.

The solution is emplo ed either neutral or acid (but not ammomca eitherhot or cold. One advantage of my process is the abilit to use ordinaryroom temperatures, althoug raising the temperature is permissible andproduces even faster action. The longer the treatment the treatment thedarker the color; the coating passes through the yellows, blues, reds,to a final black, and any desired color can beretained merely bystopping the treatment. Generally the treated article is finished merelyby rinsing, although a coating of paint or enamel can be applied ifdesired and adheres better than to the naked metal.

Having thus described my invention what I claim is:

1. The process of coating articles consisting at least superficially ofzinc or cadmium which contains the step of subjecting them to the actionof a solution containing a water soluble molybdate and a sulphuric acidcompound.

2. The process of coating articles consisting at least superficially ofzinc or cadmium which contains the step of subjecting them to the actionof a solution containing ammonium molybdate and ammonium sul hate.

3. A dipping solution for zinc an cadmium articles containin ammoniummolybdate and ammonium phate.

4. A dipping solution for zinc and cadmium artlcles containin a solublemolybdate and a, sul huric acid compound.

5. A non-a aline dipping solution for zinc and cadmium articlescontaining a solublo molybdate and a, seoond soluble salt, such secondsalt being one which is not alkaline m and does not precipitatemolybdenum.

In testimony whereof I hereunto aflix my signature.

ALADAB PACZ.

signature.

I ALADAR PACZ.

CERTIFICATE OF CORRECTION.

Patent No. 1,784,106. Granted December 9, 1930, to

ALADAR PAGZ.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,lines 69 to 71 strikeout the words and period "I prefer to employ anamount of this activatihg material in excess of the molybdate."; samepage, line 78, strike out the words the treatment"; and that the saidLetters Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of February,. A. D. 1931.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,784,106. Granted December 9, 1930, to

ALADAR PACZ.

it is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,lines 69 to 71, strike out the words and period "I prefer to employ anamount of this activating material in excess of the molybdate."; samepage, line 78, strike out the words "the treatment"; and that the saidLetters Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of February, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

